Android SQLite Database

SQLite database

Sqlitedatabase//Management operations database
Management
OpenDatabase//Open
Openorcreatedatabase//Open or create
Operations and additions and changes to check
EXECSQL//Execute SQL statement
Insert//Increment
Update//change
Delete//delete
Query//Check
Rawquery//sql Statement Check
Things
BeginTransaction//Start
Endtransaction//End
Cursor//Query Results
Move

Sqliteopenhelper//Management database and version updates
OnCreate//CREATE database callback for the first time
Onupgrade//callback when database version is updated
Getreadabledatabase//Read the way Open
Getwritabledatabase//write the way Open
Close//Turn off all open sqlitedatabase

Demo1 Inserting and querying data

 Public classDBTestextendsActivity {sqlitedatabase db; Button Bn=NULL;    ListView ListView; @Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.main);        Inittitle ();        InitData ();    Initview (); }     Public voidInittitle () {} Public voidInitData () {db= Sqlitedatabase.openorcreatedatabase ( This. Getfilesdir (). toString () + "/MY.DB3",NULL); Try{db.execsql ("CREATE Table News_inf (_id integer" + "PRIMARY key AutoIncrement," + "news_title varchar ()," + "NE Ws_content varchar (255)) "); } Catch(Exception e) {log.i ("TAG", "E---" +e); }    }     Public voidInitview () {ListView=(ListView) Findviewbyid (r.id.show); Bn=(Button) Findviewbyid (R.id.ok);        Querydata (); Bn.setonclicklistener (NewOnclicklistener () {@Override Public voidOnClick (View source) {String title=((EditText) Findviewbyid (R.id.title)). GetText (). toString (); String content=((EditText) Findviewbyid (r.id.content)). GetText (). toString (); Try {                    //Inserting Datainsertdata (DB, title, content);                Querydata (); } Catch(sqliteexception se) {}}}); }    //Inserting Data    Private voidInsertData (sqlitedatabase db, string title, string content) {//Execute INSERT statementDb.execsql ("INSERT into news_inf values (null,?,?)",Newstring[] {title, content}); }    //Querying Data    Private voidQuerydata () {cursor cursor= Db.rawquery ("SELECT * from News_inf",NULL); Simplecursoradapter Adapter=NewSimplecursoradapter (DBTest. This, R.layout.line, Cursor,Newstring[] {"News_title", "News_content"},New int[] {r.id.my_title, r.id.my_content}, Cursoradapter.flag_register_content_observer);    Listview.setadapter (adapter); } @Override Public voidOnDestroy () {Super. OnDestroy (); //Close Sqlitedatabase When exiting the program        if(db! =NULL&&Db.isopen ())        {Db.close (); }    }}

Demo2 Word Book

 Public classDictextendsActivityImplementsview.onclicklistener{Mydatabasehelper DBHelper; Button Insert=NULL; Button Search=NULL; @Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);                Setcontentview (R.layout.main);        Inittitle ();        InitData ();            Initview (); }         Public voidInittitle () {} Public voidInitData () {//Create a Mydatabasehelper object that specifies a database version of 1, where relative paths are used.//The database files are automatically saved in the databases directory of the program's Data folder. DBHelper =NewMydatabasehelper ( This, "Mydict.db3", 1); }     Public voidInitview () {Insert=(Button) Findviewbyid (R.id.insert); Search=(Button) Findviewbyid (R.id.search); Insert.setonclicklistener ( This); Search.setonclicklistener ( This); } @Override Public voidOnClick (View v) {Switch(V.getid ()) { CaseR.id.insert://InsertString Word =((EditText) Findviewbyid (R.id.word)). GetText (). toString (); String Detail=((EditText) Findviewbyid (R.id.detail)). GetText (). toString ();                        InsertData (Dbhelper.getreadabledatabase (), Word, detail);  Break;  CaseR.id.search://Search//Get user InputString key =((EditText) Findviewbyid (R.id.key)). GetText (). toString (); //Execute Querycursor cursor =dbhelper.getreadabledatabase (). Rawquery ("SELECT * from Dict where is word like?" Or detail like? ",                    Newstring[] {"%" + key + "%", "%" + key + "%" }); Bundle Data=NewBundle (); Data.putserializable ("Data", convercursortolist (cursor)); Intent Intent=NewIntent (Dict. This, Resultactivity.class);            Intent.putextras (data);            StartActivity (Intent);  Break; default:             Break; }    }    //Insert    Private voidInsertData (sqlitedatabase db, String Word, string detail) {Db.execsql ("INSERT into dict values (null,?,?)",Newstring[] {word, detail}); Toast.maketext (Dict. This, "Add new words to success!" ", 8000). Show (); }        //Query result Goto collection    protectedArraylist<map<string, string>>convercursortolist (cursor cursor) {ArrayList<map<string, string>> result =NewArraylist<map<string, string>>(); //traversing the cursor result set         while(Cursor.movetonext ()) {//storing data in a result set in ArrayListmap<string, string> map =NewHashmap<string, string>(); //Remove values from column 2nd, column 3rd in the query recordMap.put ("word", cursor.getstring (1)); Map.put ("Detail", cursor.getstring (2));        Result.add (map); }        returnresult; } @Override Public voidOnDestroy () {Super. OnDestroy (); //close sqlitedatabase in Mydatabasehelper when exiting the program        if(DBHelper! =NULL) {dbhelper.close (); }    }}

 Public classMydatabasehelperextendsSqliteopenhelper {FinalString create_table_sql = "CREATE TABLE dict (_id integer primary" + "key autoincrement, Word, detail)";  PublicMydatabasehelper (context context, String name,intversion) {        Super(Context, Name,NULL, version); } @Override Public voidonCreate (Sqlitedatabase db) {//automatically create tables when using the database for the first timeDb.execsql (Create_table_sql); } @Override Public voidOnupgrade (Sqlitedatabase db,intOldversion,intnewversion) {System.out.println ("--------OnUpdate called--------" + oldversion + "--->" +newversion); }}

 Public classResultactivityextendsActivity {List<map<string, string>>list; @Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);                Setcontentview (R.layout.popup);        Inittitle ();        InitData ();            Initview (); }         Public voidInittitle () {} Public voidInitData () {list= (list<map<string, string>>) getintent (). Getextras (). getserializable ("Data")); }     Public voidInitview () {ListView ListView=(ListView) Findviewbyid (r.id.show); Simpleadapter Adapter=NewSimpleadapter (resultactivity. This, List, R.layout.line,NewString[] {"word",        "Detail"},New int[] {r.id.word, r.id.detail});    Listview.setadapter (adapter); }        }

Code See https://github.com/huanyi0723/SQLiteDemo/

Android SQLite Database